Metallic closure



Feb. 25, 1941. R, McCOMBS METALLIC cnosums Filed June 50, 1934 I I I I I.0 I I I I I I i only by mutilation of the outer shell.

Patented Feb. 25, 1941 PATENT OFFICE METALLIC CLOSURE Arnold It.McCombs, Lancaster Township,

Lancaster County,

Pennsylvania Pa., assignor to Armstrong Cork Company, Lancaster,

Pa., a corporation of Application June 30, 1934, Serial No. 733,195

12 Claims.

My invention relates to metallic closures and more particularly to theso-called double shell closures commonly used in sealing bottles andjars. These double shell closures are generally formed of an inner cap,which is provided with means for removably securing the cap to areceptacle, and an outer shell telescoped over the inner cap andcovering the skirt and at least a portion of the top thereof. The outershell is usually smooth surfaced throughout for appearance and in orderto permit decoration of the top and skirt. The shell may, however, beembossed or otherwise formed as desired. The cap and shell are formed oflight-weight sheet metal, such as tin plate, which is readily drawn andshaped to the desired contour.

One of the major problems incident to the manufacture of a closure ofthis type is to prevent relative rotation of the cap with respect to theouter shell. The closures are usually so constructed that they areinseparable without mutilation and upon sticking of the componentengaging means, such as screw threads, caused by the application of theclosure to the receptacle with great turning effort or by reason ofadhesion, the turning effort required to overcome such friction oradhesion is greater than that required to cause the locking means tofail, whereupon, the outer shell rotates while the cap remainsimmovable. The cap is then removable As an example, a'28 millimeterscrew closure having well formed threads and applied to a properlyfinished glass container in the usual manner will require an average of13.4 pound inches turning effort for removal, whereas, the same closurewhen applied tightly or adhesively secured by reason of corrosion orseepage of the contents of the receptacle, may require as much as 30pound inches turning effort for removal. It will be apparent, therefore,that the interlocking of the cap and shell must be such that relativerotav tion of the parts will not occur by-reason of the excess stressrequired to remove a tight fitting closure.

Various types of locking constructions have been suggested, many ofwhich are commercially impracticable and others, while they can beproduced and are effective for preventing such relative rotation,require intricate machinery for manufacture and assembly and arerelatively expensive to produce.

It is an object of my invention to provide an improved type of closurein which relative rotation of the inner cap with respect to the outer Myinvention contemplates a. closure in which 10 thereceptacle engagingportion is held in fixed position with respect to the outer shell bymeans of a flange provided on the skirt of the inner portion terminatingin a cut surface, which when urged into engagement with the skirt of the15 outer shell, causes frictional or cutting engagement, preventingrelative rotation of the parts. In the preferred embodiment, anoutwardly and downwardly extending flange is provided on the skirt ofthe inner cap, which flange is urged upwardly and outwardly into firmengagement with the skirt of the outer shell. Stated in other words, theoutwardly and downwardly extending flange is capable of being flexedwhereby the diameter thereof may be decreased to permit ready assemblyof the cap and shell and increased to cause locking engagement of thecomponent parts.

The method consists in urging an outwardly extending flange terminatingin a cut surface into engagement with the inner surface of the skirt ofan outer shell telescoped over. an inner cap, upon the skirt of whichsaid flange is formed, by changing the diameter of at least one of theparts whereby the cut surface firmly engages the skirt of the outershell and prevents relative rotation between the cap and shell. Themethod further contemplates urging an outwardly and downwardly extendingflange upwardly and outwardly into engagement with the inner surface of4 the skirt of the outer shell.

In order that my invention may be more clearly .understood, I willdescribe the same in connec- Qtion with the attached drawing in which--Figure 1 is an exploded view partly in elevation and partly in sectionshowing an outer shell and an inner cap prior to assembly;

Figure 2 is a view partly in elevation and partly in section showing thepreferred embodiment of my new closure;

Figure 3 is a view partly in elevation and partly in section showing amodified construction;

Figure 4 is an enlarged section taken on the line IV-IV of Figure 3;

Figure 5 is a diagrammatic view illustrating the relative position ofthe flange with respect to the outer shell; and

Figures 6, '7, 8 and 9 are broken sectional views showing modifiedembodiments of my invention.

Referring first to Figure 1, an outer shell 2 is formed from a blank ofsheet metal, such for example as 32 gauge tin plate which may be firstsuitably decorated as by lithographing. This shell is provided with atop portion 3 and a depending skirt portion 4 which is formed by asingle, simple drawing operation familiar to those skilled in the art.

An inner cap, generally indicated by the numeral 5, is formed from ablank of tin plate in two operations; a shell similar to the shell 2,but having the exposed edges of the skirt formed into a flange, beingfirst drawn and this shell thereafter passing into engagement with ascrew threading and knurling die whereby a thread 6 and a knurledportion 1 are formed on the skirt. As shown in the drawing, the top 8may be flat, or if desired, may be contoured to provide a liner forcingannulus and have a dome shaped top as shown in Figure 6. In the eventthe top 8 be domed, as shown in Figure 6, it is desirable to have thetop 3 of the outer shell also domed, with the radius of curvature ofboth the same, so that the outer shell will not be deformed uponsubsequent assembly of the two parts. Screw threads have beenillustrated as providing means for removably securing the closure to areceptacle. Other types of engaging means may be substituted for thesescrew thread formations.

According to my preferred embodiment, a flange 9 is provided upon theexposed edge of the skirt of the inner shell terminating in a cutsurface. As pointed out above, this flange may be formed during theoriginal drawing operation and if so formed it will have a tendency tobe irregularly shaped, or, in other words, will vary in length from theline of intersection with the skirt to the edge thereof. It is desirableto trim this flange to a uniform and desired size and this may beconveniently done by means of a horizontal punch type cutting machine.

In Figure 1, the flange extends at an angle of about 105 with respect tothe skirt of the cap. This angle permits ready assembly and subsequentdeformation. The particular angle to be employed is not criticalalthough the flange should, in order to provide the preferred biasingaction, extend outwardly and downwardly. As is better illustrated inFigure 5, the flange length from the line of intersection It) with theskirt to the exposed edge ll of the flange 9 is greater than thedistance from any point on the line ID to a corresponding point I2 onthe inner surface of the skirt of the outer shell lying in a planenormal to the axis of the cap, or stated in other words, an arc swungfrom any point on the line of intersection l0 having a radius equivalentto the skirt length will intersect the inner surface of the skirt of theouter shell. This is desirable in order that upon upward movement of theflange 9 about the line of intersection III, the flange will firmlyengage the surface l3 before reaching a position normal to the axis ofthe cap. The difference in length between the flange 9 and the lineIll-42 will depend to some extent upon the deformability of the outershell.

To insure that the can be properly positioned with respect to the outershell, I prefer to have the flange formed with an outer diameterslightly greater than the inner diameter of the shell. The flange issufliciently flexible to permit telescoping of the two parts and theinner cap having a flange about .002" greater in diameter than the innerdiameter of the outer shell is readilyassembled by means of an insertingplunger. The cap and shell may be forced into position with the headportions 3 and 8 in engagement, or, if desired, a cardboard or othercushioning disk D may be inserted therebetween as shown in Figure 7.

After telescoping, the cut surface of the flange is urged into firmengagement with the inner surface of the skirt of the shell. This may beaccomplished by decreasing the inner diameter of the skirt of the shellor by increasing the diameter of the flange on the cap, or both. Thediameter of the skirt may be reduced by curling the exposed edge thereofunder the flange whereby the skirt will curl inwardly from the line ofcontact with the flange, whereby the frictional grip of the metal parts,enhanced by the action of the cut surface, will prevent rotation.

I prefer, however, to urge the flange 9 upwardly whereby the outerdiameter thereof is increased and the cut surface flrmly engages theinner surface of the outer shell. Various means may be employed forurging the flange upwardly, such for example as a suitably shapedplunger having an outer diameter substantially the same as the innerdiameter of the outer shell. The cut surface has a tendency to besomewhat roughened as is common in cut metallic surfaces of this typeand this surface upon being forced upwardly against the metal of theouter shell forms microscopic grooves therein which greatly enhance thefrictional grip. The flange which is normally biased downwardly and outof the position it now assumes should preferably be held in strained orupward position, which, as shown in Figure 2, lies at an angle slightlygreater than with respect to the skirt of the cap. It is desirable,although not essential, that the entire cut surface ll of the flangeengage the shell because of the increased frictional grip providedthereby. There may be a slight deformation of the outer shell by reasonof the pressure applied by the flange if 32 gauge tin plate is used, butthis will not be noticeable. The flange may be held in proper positionby any simple deformation of the skirt of the outer shell below the lineof contact with the flange. A plurality of indentations may be employedor the exposed edge of the skirt may be turned under the flange therebyholding it in strained position. Any angularly extending por- (tionprovided on the outer shell which holds the flange in such positionwithout materially weakening the frictional grip will be satisfactory.

If desired, the skirt of the outer shell may be deformed prior toinsertion of the cap and the flange then urged into its strainedposition snapping under the deformed portion of the shell. According to-my preferred embodiment, however, the flange is urged upwardly and theouter shell deformed by a single operation. As shown in Figure 2, thisis accomplished by forming an inwardly, upwardly and outwardly extendingbead l5 into engagement with the flange 9 whereby the flange is urgedinto firm engagement with the shell and held in that position by thebead. A simple crimping or curling tool of the type now employed in themetallic closure art may be used for this purpose. The bead may beturned so that the cut edge thereof engages the inner surface of theshell. It is desirable that no out surfaces be exposed which might havea tendency to become corroded upon contact with the contents of thebottle. A somewhat enhanced gripping action will be obtained,

however, if the cut surfaceof the exposed edgeis illustrated in whichthe flange l6 has formedv on the exposed edge thereof a plurality ofserrations or tooth-like elements l'l. These may be formed during theflange trimming operation by the use of a suitably shaped cutting die. Ihave found that if the portion between the cuts is about four times thewidth of the cut a desirable gripping action is obtained. This isprobably due to the fact that, upon being urged upwardly, the tooth-likeelements I1 have a tendency to scrape the metal, leaving the metal uncutin the portions l8 between the teeth. In other words, the skirt of theouter shell is provided with shallow indentations corresponding to theteeth I! and raised portions l8 therebetween. This forms a highlydesirable interlocking engagement of the parts which is enhanced byreason of the fact that the teeth I! engage the surface of the skirt andalso aid in preventing relative rotation. The formation or shape of theserrated edge is not controlling, although I have found that whenserrations terminating in sharp points have been employed they have atendency to become distorted upon the application of pressure and arenot as effective as relatively flat surfaces with narrower slots cuttherebetween.

While it is desirable that the flange terminate in a cut surface, itwill be understood that the flange may be provided with a bead or turnedin portion B as shown in Figure 8 which will present a smooth surfacefor engagement with the outer shell. This will eliminate the trimmingoperation referred to above but will necessitate another formingoperation.

As is common in this art, the outer covering has been called a shell andthe inner portion a cap. It. will be understood that the shell need notcover the entire top portion, but if it be as shown in the drawing,Figuresl to 5, the cap may be in the form of an annulus A as shown inFigure 9 having a shoulder S rather than a complete top with engagingmeans and a deformable flange. The preferred construction, however, isthe form illustrated, wherein both shell and cap are provided with acomplete top and skirt.

While I have described and illustrated the preferred embodiment of myinvention, it will be understood that the invention is not so limitedbut may be otherwise embodied within the scope of the following claims.

I claim:

1. A double shell closure comprising an inner metallic cap and an outermetallic shell, an outwardly and downwardly directed expansible flangeon the skirt of the cap engaging the inner surface of the shell andbiased downwardly, and an angularly extending portion on the skirt ofthe shell engaged with the lower face of said flange and holding saidflange in strained position against the tendency to return to its normalposition.

2. A double shell closure comprising an inner metali'c cap and an outermetallic shell, an outwardly and downwardly directed expansible flangeon the skirt of the cap engaging the inner surface of the shell andbiased downwardly, and a bead formed on the exposed edge of the skirt ofsaid shell holding said flange in firm engagement with said shell and instrained position.

3. A double shell closure comprising an inner metallic cap and an outermetallic shell, an outwardly and downwardly directed expansible flangeon the skirt of the cap lying at anangle greater than 90 with respect tothe skirt of said cap and terminating in a cut surface lying in flrmengagement with and penetrating the material of the skirt of said shell,and an angularly extending portion on the skirt of said shell engagedwith the lower face of said flange and holding said flange in fixedposition.

4. A double shell closure comprising an inner metallic cap and an outermetallic shell, an outwardly and downwardly directed expansible flangeon the skirt of the cap having a serrated surface lying in firmengagement with the skirt of the outer shell, said flange being biaseddownwardly and an angularly extending portion on the skirt of the shellbelow the line of contact of said flange holding said flange in strainedposition.

5. Adouble shell closure comprising an inner metallic cap and an outermetallic shell, a flange on the skirt of the cap having a serratedsurface in which the tooth-like elements are at least four times thewidth of the cut portions, said tooth-like elements engaging the innersurface of the skirt of the outer shell, raised portions on the skirt ofthe outer shell intermediate the tooth-like elements and a bead on theskirt of the outer shell in firm engagement with said flange. i

6. A double shell closure comprising an inner metallic cap and an outermetallic shell, a flange on the skirt of the cap biased downwardlyandterminating in a cut, serrated surface, the serrated surface of theflange engaging the skirt of the outer shell, with raised portionsintermediate adjacent serrations, and an angularly extending portion onthe skirt of the outer shell below the line of contact of the flangeholding said flange in strained position.

7. A double shell closure comprising an inner cap having a top and askirt, an outwardly directed expansible flange formed on said skirtbiased downwardly, an outer shell telescoped over the cap, a bead formedon the exposed edge of the skirt of said shell terminating in a cutsurface firmly engaging said flange and holding the same in strainedposition.

8. A double shell closure comprising an inner cap having a top and adepending skirt provided with means for removably securing said closureto a receptacle, an outwardly and downwardly directed expansible flangeformed on said skirt biased downwardly, said flange normally extendingat an angle substantially greater than 90 with respect to the skirt, anouter shell hav ing a top and a depending skirt, a bead formed on theend of said skirt engaging the flange on the skirt of said cap andurging the same into firm engagement with the skirt of the outer shellat an angle of substantially 90 with respect to the skirt or said capand holding the same in strained position.

'9. A double shell closure comprising a screw threaded cap telescopedwithin an outer shell,

an expansible flange on the skirt of the inner cap normally lying in afrusto-conical surface, a bead formed on the exposed edge of the skirtof the outer shell engaging said flange and holding the same in firmengagement with and penetrating the material of the skirt of the outershell and in a geometric surface substantially appreaching a planenormal to the axis of the cap against the tendency to lie in afrusto-conical surface.

10. A double shell closure comprising an inner metallic cap and an outermetallic shell, an out wardly directed and downwardly biased expansibleflange on the skirt of the cap terminating in a cut surface lying infirm engagement with the skirt of the outer shell and a bead on theskirt of the outer shell terminating in a cut surface lying in firmengagement with said flange and holding the same in strained position.

11. A screw cap embodying therein a skirted outer shell, and an innershell inclosed thereby having a skirt provided with means adapted toengage complementary means upon a container,

upon a container, and an outwardly and downwardly directed flange aboutthe bottom thereof having a plurality of deformed edge tangs, said tangspenetrating the material of the skirt of the outer shell, and theinwardly turned edge of the skirt of the outer shell frictionallyengaging said flange intermediate said tangs and the skirt of the innershell, and said tangs being clamped between said turned portion and theskirt of the outer shell.

ARNOLD R. MCCOMBS.

